Snake Devil

The Snake Devil rears up as a gigantic serpent, its most unsettling trait a yawning maw lined not with fangs but with interlocking limbs and grasping hands. Green scales sheathe the length of its body, and a single crimson eye set against a black sclera completes the picture.

Whatever drives the Snake Devil from within is never spelled out. In practice it acts as a pure instrument of Sawatari's will, obeying her spoken orders and gestures without betraying any agenda of its own. Tellingly, it eventually turns on her, killing Sawatari as she is being taken into custody, possibly as a clause written into the pact the two shared.

The serpent carries the standard devil capacity to forge contracts with humans for a price. Its one known pact is with Akane Sawatari, who calls it forth and steers it through voice commands paired with hand movements, surrendering a single fingernail for every order she gives. Because those gestures are essential, binding her hands together strips her of any control over it.

Its signature power is absorption and release. The Snake Devil can engulf another devil inside its enormous mouth and hold it there, then expel that being later to do battle in its place, fully restored to health upon coming out. Sawatari triggers the two effects with the calls to swallow a target whole and to spit it back out. The release in particular appears to demand an extra toll; summoning the consumed Ghost Devil against Aki Hayakawa costs her not just a nail but a nosebleed as well.

These powers anchor the devil's role across the Katana Man arc, where it swallows Himeno's Ghost Devil, lunges at Kobeni, and is later made to release that Ghost Devil to fight on Sawatari's side. Following Sawatari's death, Makima gains use of the lingering contract by taking possession of her body.